1. Field of the Invention
The present invention relates to a grip system for hand tools and instruments. More particularly, this invention concerns an improved, customized grip system which is applicable to hand tools of different designs, including pivoted hand tools, such as scissors, pincers, pliers, surgical needle holders; single grip hand tools, such as a hammer, hatchet, screwdriver, knife; other hand and power shop or garden tools; small hand-held appliances, such as a hair dryer and curler, and brushes; single grip sporting goods, such as a racquet or paddle, fishing pole, pistol grip, and archery equipment; and levers with an end hinge point, such as forceps. The grip system can be applied to most any object grasped with one or both hands in the same place by the same person, such as musical instruments.
In the traditional type of hand tools no special attention is paid to the way the user holds the tools in the hand Either no means is provided to keep the thumb and fingers in defined positions (e.g. conventional hammers, knives, garden tools) or the thumb and one or more fingers are forced into uncomfortable positions, with no or little attention to the anatomy of the individual user's hand (e.g scissors, surgical needle holders). This is particularly unsatisfactory in the case of surgical instruments, during the use of which the doctor's hand must perform a variety of types of movements with high precision; or in single grip cutting instruments, such as a knife, where slippage of the grip could result in injury to the user. The design of the handle or grip of conventional tools, due to their being usable by a great variety of hand anatomies, may result in the instrument slipping in the hand during use or lessening the force that can be exerted. Furthermore, the use of an instrument which is uncomfortable to hold for tedious work may tend to increase the chance of an error or early fatigue.
2. Description of the Prior Art
There are numerous attempts known in the art for designing various grips for hand tools, especially surgical instruments that improve the performance of these articles during operation.
U.S. Pat. No. 2,669,993 shows a bicapsular grip for pivoted surgical instruments. The instruments are equipped with two capsular members, one for housing the thumb's ball and the other one the index finger's ball. The capsular member housing the thumb's ball is integral with a ring-like member similar to the ring occupied by the thumb in ordinary pivoted instruments, such as scissors. The inner surface of this ring-like member is bevelled such that throughout its entire length, it will contact the surface of the thumb without exerting pressure. The middle finger is accommodated in a half-ring. The disclosed instruments are cross-manual, i.e. are designed to be held across the hand, the thumb pointing outward relative to the lever to which the capsular member housing the thumb is attached. One object of the invention disclosed in this publication is to increase considerably the tactile sensitivity and "conductibility" of the instrument.
U.S. Pat. No. 3,407,816 discloses pivoted surgical instruments with handles, one fitting in the user's hand and the other being actuated by the user's thumb. The described handles are "aximanual", i.e. are designed to be held in the direction of the axis of the hand. Unlike conventional scissors, only the handle engaging a "capsule" or thumb piece is moved during operation. The design contains capsules intended to be engaged by the index finger and the middle finger, respectively. The aximanual handling of the instruments brings about a more efficient way of performing operations.
U.S. Pat. No. 4,140,124 is directed to pivoted surgical instruments with a generally triangular first handle for fitting into the palm, and a second handle for receiving the thumb. The instrument extends along the axis of the user's hands and may therefore be termed as an aximanual instrument. The palm of the hand supports the instruments and holds stationary the lower branch so that the upper blade can be aimed without oscillation and accomplish its objective with great precision.
A surgical cutting instrument is disclosed in U.S. Pat. No. 4,726,371. The instrument is carried on the small finger of a surgeon's hand to enable to make cuts while the surgeon holds another instrument in the same hand. The cutting instrument comprises a sleeve mounted on the surgeon's small finger, and a scissors mounted on the sleeve.
None of these publications addresses the problem of accommodating hands of various sizes and shapes in rest position, known as "the position of function" in the medical literature, around a variety of hand tools and instruments, in order to maximize power and perception of the object to be manipulated during use of the instrument.